Theory and practice -- Consciousness: concepts, neurobiology, terminology of impairments, theoretical models and philosophical background -- Consciousness: its neurological relevance -- Syndromes of impaired consciousness -- Delirium in the critically ill patient -- Coma and stupor -- Herniation -- Vegetative and minimally conscious states -- Specific entities -- Metabolic encephalopathies -- Nutritional disorders -- Coma induced by intoxication -- Ischemic stroke and anoxic-ischemic encephalopathy -- Infectious etiologies of altered consciousness -- Traumatic brain injury -- Seizures and impairment of consciousness -- Syncope -- Altered consciousness associated with brain neoplasms -- Abnormal conscious state and coma in transplant recipients -- Pregnancy and coma -- Psychogenic unresponsiveness and nonepileptic seizures -- Coma in childhood -- Management issues -- Management of the comatose patient -- Ethical issues in the management of patients with impaired consciousness.